Cheryl Warfield , known to our area from her performances in Il Trovatore, Carmen and Don Giovanni with the WCO, appeared this season with the Lyric Opera of Chicago in Porgy and Bess and returns to us to present Beethoven's dramatic aria, "Ah, perfido!" This aria, perhaps better described as a dramatic scene for soprano and orchestra, takes the heroine from her first impassioned outbreak, "Oh, betrayer!" through an amazing gamut of emotional states ranging from outward rage to introverted self mortification, and involving wildly diverse musical expressions all skillfully crafted by Beethoven into a "mini-opera". Contrasting this almost superhuman level of passion, Frederick Delius' "On Hearing the First Cuckoo in Spring" and "Summer Night on the River" are studies in tranquility and tenderness, and Mozart's Overture to Cosi fan tutte stands as a sort of philosophical summing up and acceptance of all the vagaries of human existence.